Here’s How Long to Set Your Shutter Speed

How long do you need to keep your shutter open for great starry sky and Milky Way shots? Usually around 12 to 15 seconds. If you leave it open any longer, you’ll get blur from the natural movement of the earth and stars—go with a shorter shutter speed than 12 seconds and you’ll have to crank the ISO on your camera so high you’ll get lots of noise and you probably won’t be happy with the results. So, start at 15 seconds, and then zoom in and check to see if the stars are nice and tack sharp. If not, then try a second or two shorter shutter speed and take a test shot. It might take you a few test shots to nail it, trying a 12-second or 13-second shutter speed, but you’ll have it nailed down really quickly, and then you won’t have to mess with it again. Now (nerd alert), if you’re the type of person that says, “Scott, I can’t experiment. I must know the exact proper setting for my lens, my f-stop, and my particular size sensor or I won’t be able to sleep at night,” don’t worry—there’s an app for that (see page 127). The PhotoPills app has a feature in it where you tell it how many megapixels your camera is, and how wide your lens is, and it will tell you exactly how long to leave your shutter open.